Mr Musk’s idea to start selling the bizarre product began as a joke in December when he pledged that if The Boring Company sold 50,000 limited edition baseball caps, it would start selling flamethrowers.

But the dangers of selling a fire-emitting device, and Mr Musk’s mischievous marketing tactics have raised questions about the legality of selling such a weapon online.

“ATF [Bureau of Alcohol, Tobacco, Firearms and Explosives] says any flamethrower with a flame shorter than 10ft is A-ok. Our design is max fun for least danger. I’d be way more scared of a steak knife,” Mr Musk said on Twitter.

The rumor that I’m secretly creating a zombie apocalypse to generate demand for flamethrowers is completely false